How can I access positional parameters after $9?

Use ${10} instead of $10. This works for BASH and KornShell, but not for older BourneShell implementations. Another way to access arbitrary positional parameters after $9 is to use for, e.g. to get the last parameter:

# Bourne
for last
do
: # nothing
done
echo "last argument is: $last"

To get an argument by number, we can use a counter:

# Bourne
n=12 # This is the number of the argument we are interested in
i=1
for arg
do
if test $i -eq $n
then
argn=$arg
break
fi
i=`expr $i + 1`
done
echo "argument number $n is: $argn"

This has the advantage of not "consuming" the arguments. If this is no problem, the shift command discards the first positional arguments:

In addition, bash and ksh93 treat the set of positional parameters as an array, and you may use parameter expansion syntax to address those elements in a variety of ways:

# Bash, ksh93
for x in "${@:(-2)}" # iterate over the last 2 parameters
for y in "${@:2}" # iterate over all parameters starting at $2
# which may be useful if we don't want to shift

Although direct access to any positional argument is possible this way, it's seldom needed. The common alternative is to use getopts to process options (e.g. "-l", or "-o filename"), and then use either for or while to process all the remaining arguments in turn. An explanation of how to process command line arguments is available in FAQ #35, and another is found at http://www.shelldorado.com/goodcoding/cmdargs.html